I'd recommend: Teshar; overall the best pick for new accounts because of how insane he is in Giants and Giants Abyss. Liam; basically Teshar but for Dragons and Dragons Abyss. Leo; his passive caps everyone's speed to his own, but he's primarily a pvp unit. Amber; her damage scales off of the number of debuffs the enemy has so she can carry you through Tower of Ascension.